Method and apparatus for code division switching

Abstract

Time division multiplexed input signals (i.e., separated into time slots) are spread in each time slot with a destination code. This spreading is applied for destination identification as opposed to signal information modulation. Each spreading signal is associated with a particular destination for a particular time slot. These spread signals are then combined on a code division bus. Output signals for retransmission to the destinations are recovered from the bus by application of despreading codes. Each despread signal has a destination code which appears in its individual time slot. In a variant code division multiplexed signals are directed to a destination by use of time slot interchanger to achieve time division switching to route the CDMA multiplexed channels.

1. A time division code switch, comprising:
 an input for accepting at least one code division modulated signal and including an input despreader to decode the at least one code division modulated signal into a plurality of Code Division Multiple Access (CDMA) beams; 
 a code bus for delivering said plurality of CDMA beams to a plurality of user despreaders at the input; 
 a time slot interchanger connected to the plurality of user despreaders to receive the CDMA beams that have been demodulated, the time slot interchanger re-arranging time slots of each frame to couple an input to a designated output; 
 a respreading circuitry connected to the designated output of the time slot interchanger; 
 a summer connected to the respreading circuitry to sum a plurality of spread signals having a common destination to form a beam directed to said destination; and 
 an output for directing the beam to said destination.